A common conversion on supplement and medication labels, where doses are sometimes given in micrograms and sometimes in milligrams.
How it works
Dividing micrograms by 1,000 gives milligrams; multiplying milligrams by 1,000 gives micrograms back. Type into either field and the other updates instantly.
What this does not include
This does not include dosing guidance — always follow the specific unit and amount on a medication or supplement label rather than converting and second-guessing it yourself.
How to use this calculator
- Enter a value in either micrograms or milligrams — the other field fills in automatically.
Frequently asked questions
Why do some labels use mcg and others use mg?
Very small doses (like vitamin B12 or vitamin D) are often expressed in micrograms to avoid a string of decimal places that milligrams would require.
Is “mcg” the same as the Greek letter mu (μg)?
Yes — both represent micrograms; “mcg” is commonly used instead of the μg symbol specifically to avoid confusion with “mg” (milligrams) on printed labels.
What’s the risk of confusing mcg and mg?
A 1,000-fold difference — mistaking micrograms for milligrams (or vice versa) on a medication dose is a serious, well-documented source of dosing errors.
